Typically, a street or road paving process entails a paver and a dump truck positioned closely ahead of the paver. Paving material carried in the load bed of the dump truck flows from the rear end of the load bed into a hopper and forms a part of the paver. Controlling the flow of paving material into the hopper is necessary since the hopper has a limited capacity. During the process of transferring paving material from the load bed to the hopper, it is necessary to tilt the upper end of the load bed. As more and more paving material is discharged from the load bed into the hopper, it is necessary to continue to raise the load bed. In some cases, the load bed is raised too high and too much paving material is discharged from the load bed. In this case, the load bed should be lowered in order to appropriately adjust the flow of paving material from the rear end of the load bed. Controlling the flow of paving material is done on the go. That is, as the paver and dump truck move forwardly, the attitude (or inclination) of the load bed of the dump truck is adjusted to provide an appropriate flow of paving material into the hopper.
This can be challenging. It is not uncommon to overfill the hopper, which results in paving material being spilled onto the road or the street, requiring time and labor to address the spill. However, what makes this especially challenging is that the person actuating and adjusting the attitude of the load bed is in the cab of the dump truck facing forwardly. It is impossible for the dump truck driver to directly see the hopper, the amount of paving material in the hopper, the paver or the operator on the paver. In order to address this problem, the conventional practice is to position a person on the roadway or street where this person walks along beside the paver. This person may be termed a signaler or a guide. His or her function is to instruct the dump truck driver on raising and lowering the load bed to provide an appropriate flow of paving material from the load bed into the hopper. The dump truck driver views the signaler or the guide through the driver's side rear view mirror. The signaler or guide communicates with the driver through hand signals or shouting.
There are a number of problems with this approach to controlling the flow of paving material from the load bed into the hopper of the paver. First, even with the help of the guide, it is still difficult to accurately control the flow of paving material from the load bed into the hopper. It is difficult for the in-cab driver to make small and precise adjustments in the attitude of the load bed that may be required from time-to-time. It is not uncommon for the adjustment to oversupply or undersupply. When there is an oversupply, spills occur. When there is an undersupply of paving material, then this impacts the overall paving efficiency, causing the paver to have to adjust its pace or even stop.
Secondly, the requirement of the guide or signaler is a cost that has to be accounted for. This increases the paving cost.
Finally, there is a safety issue. Often paving is performed on interstate or busy highways. With this conventional approach, the guide or signaler walks in close proximity to busy traffic. Because the guide or the signaler is busy communicating with the dump truck driver, it is possible that the guide or signaler may be less attentive than is prudent.
Therefore, there is a need for a paving system and process that addresses these problems. In particular, there is a need for a system and process for controlling the flow of paving material from the load bed to the hopper of the paver that enables accurate and precise control and at the same time, eliminates the need for a walking guide or signaler.